Spray drying apparatus



K. SCHULTZ SPRAY DRYING APPARATUS Mar ch 31, 1936.

2 Sheet-Sheet 1 Filed May 7, 1954 March 31,1936. K, HU T 2,035,673

SPRAY DRYING APPARATUS Filed May 7, 1934 2 Sheets-Sheet 2 Patented an.31, 136

SPRAY DRG APPATUS Kristian Schultz, Chicago, Ell assignor to our andCompany, Chicago, 111., a corporation of Illinois Application May 7,1934, Serial No. 724,338

10 Claims.

The present invention pertains to apparatus for evaporatingsolid-containing liquids or liquidcontaining solids, of which milk andeggs are typical, to varying degrees of dryness.

The principal objects of the invention are the provision of apparatus oflarge and elhcient capacity in a form requiring relatively small spacefor installation and operation; the embodiment in such apparatus ofmeans for the regulation of the quantity, temperature and humidity ofthe treating gas such as air, and of the period of time during which thematerial is subject to treatment; control of flow of the treating gaswhereby most efiiciently to prevent adherence to the walls of thetreating chamber, avoiding dead areas and eddy currents W thin thedrying chain? her, and equalization of the treatment of all portions ofthe material as predetermined in respect of time, temperature andultimate dryness of the product.

To facilitate an understanding of the inven tion, preferred and modifiedembodiments of the same are hereinafter described in connection with theaccompanying drawings, wherein Fig. l is a side elevation partly invertical section of an apparatus embodying the invention;

Fig. 2 is a h izontal section on the irregular iine 22 of Fig. i;

Fig. 3 is a partial vertical section through a slightly modified form ofthe apparatus;

Fig. 4 is a similar view illustrating another modification; and

Fig. 5 is a similar view of still another.

Further modifications may be made in struc-' ture without departure fromthe essence of the invention, wherefore it will be understood that thepreferred structure and modifications thereof are set forth by way ofillustration rather than as limiting the scope of the invention otherthan as required by the prior art.

Having reference to Fig. 1, it will be observed that the apparatuscomprises a drying chamber ll having walls formed by louvers' i 2disposed in slightly overlapping relation to present therebetweencylindrical substantially parallel openings Hi from the exterior to theinterior of the drying chamber. These louvers may, as shown, be arrangedat a slight inclination to the horizontal in a continuous spiralformation whereby the openings l3, while in substantially horizontalparallel planes, will have a spiral relation to the axis of the dryingchamber.

The imperforate outer wall 14 surrounding and in spaced relation to thedrying chamber are preferably slightly conical, contracting downspace l6through an annular opening 20 about.

the upper end of the drying chamber.

The gas pressure is controlled by the regulation of the blower ll andits temperature by heati ing elements under control of a thermostaticdevice indicated at 2! The annular opening 20 from the manifold chamberit to the distributing space It is fitted with pendant hinged vanes 22which may be adjusted relative to the vertical whereby to permit thetreating gas to enter the distributing space in a vertical direction orat an inclination to the vertical, in which latter case the gas withinthe distributing space is given a whirling direction of travel.

Below the drying chamber the casing 23 ex-= tends downwardly as acontinuation of the wall 'Hi and laterally at 2 4 where it enters aconventional cyclone collector 25 provided with the hopper-like lowerportion 26 whence it falls through the valved neck 21 into any suitabledepository. The dust-freed treating gas is discharged from the collector25 through the valved Stack 28.

The particular type of dust collector employed is immaterial.

Obviously, instead of or in addition to employing a blower as I! toforce the treating gas under pressure through the system, an exhaustblower lla may be installed in the stack 28 or at another suitable pointwhereby to draw the treating gas from the heater through the dryingchamber and the collector chamber.

At the upper end of the drying chamber there may be positioned anupwardly convex cone 29 projecting into the manifold chamberl9forequalizing the amount of gas entering the annular distributingspace Hi. This conical cover 29, forming a closure at the upper end ofthe drying chamber may advantageously be provided with a number of smallapertures 30 through which a modicum of gas will pass whereby to avoidany dead air space, back-lash or eddy currents beneath the same. Suchamount of treating gasas enters through the cover is pre- As thematerial is discharged as a fine spray from the nozzle 3| in a downwardand outward direction toward the wall l2, it is met by the continuousapproximately annular spiral sheets of gas entering through the louveropening l3 and prevented from coming into physical contactwith the wall,while the gas entering through the openings 30 surrounds the spraywithin the coned cover and as it descends, mingles with the gas currentsentering through the louver openings to efiect thorough commingling ofthe treating gas in the central portion of the drying chamber. Thespiral direction imparted to the treating gas in the distributingchamber l6 by the vanes 22, supplemented by spiral arrangement of thelouver openings, has the effect of creating a whirlpool or vortex withinthe drying chamber whereby the material being evaporated is thoroughlyagitated and at the same time directed towards the axis of the chamber.None of the material can come in contact with the side walls, thusavoiding any possibility of adhesion thereto. The downwardly directedannular curtain of gas just inside the walls of the casing serve toinsulate the walls from the material and to virtually form a barrieragainst the progress of the material outwardly beyond this annularcurtain.

The modification shown in Fig. 3 differs from that previously describedonly in, the comformation of the cover member of the upper end of thedrying chamber. Herein it is shown as being .a fiat plate 29a and theformation of eddy currents thereunder is minimized by the location ofthe spray nozzle 3| in substantially the same plane as the uppermostlouver opening.

In Fig. 4 a conical cover member 2917 is shown as employed somewhatsimilar to that of Fig. 1, Here, however, the cone is made up of louversI21; and the treating gas is introduced through an nular louver openingsl3a whereby annular sheets of gas insulate the inner wall of the conefrom the sprayed material and also preclude the formation of any deadspace or eddy currents.

In Fig. 5 is shown a cover member 290 downwardly coned with the nozzle31 disposed at the apex of the cone. Here the inner wall of the cone isswept by the sheets of gas entering through the louver openings [3between the louvers l2 which latter may have their inclination to thevertical slightly modified in that area surrounding the cone whereby theincoming sheets of gas will impinge against and sweep the inner wall ofthe cone.

It ist'obe understood that directional terms as used herein, such asvertical, horizontal, down: ward, upward, above, below and the like,have application only to relative arrangement as shown in the drawings.

I claim:

1. Evaporating apparatus comprising a drying chamber having wallsprovided with openings thereto longitudinally spaced and extendingsubstantially parallel to each other, an outer enclosingwall spaced fromthe said chamber to provide an annular gas distributing space, means tosupply treating gas to said distributing space,

adjustable means to control the direction of flow within saiddistributing space, and means to introduce the material to be treated infinely divided condition axially of the drying chamber.

2. Evaporating apparatus comprising a drying chamber having wallsprovided with openings thereto longitudinally spaced and extendingsubstantially parallel to each other, an outer enclosing wall spacedfrom the said chamber to provide an annular gas distributing space,means to supply treating gas to said distributing space, adjustablemeans to control the direction of flow within said distributing space,means to introduce the material to be treated in finely dividedcondition axially of the drying chamber, and means to condition said gasas to temperature, pressure, and quantity.

3. Evaporating apparatus comprising a vertically disposed drying chamberof generally cylindrical shape having walls provided with louveropenings thereto longitudinally spaced apart and extending substantiallyparallel to each other, an outer enclosing wall atan inclination to andspaced from the said chamber to provide an annular downwardly reducedgas distributing space, means to supply treating gas downwardly to saiddistributing space, means to condition said gas, means to introduce thematerial to be treated in finely divided condition axially of thechamber before reaching the first louver openings, and means to withdrawthe gas and dried material from the drying chamber.

4. Evaporating apparatus comprising an upright drying chamber ofgenerally cylindrical shape having walls provided with louver openingsthereinto longitudinally spaced apart' and. extending substantiallyparallel to each other with interspaces directed longitudinally of thechamber, an outer enclosing wall spaced from the said chamber at aninclination to provide an annular gas distributing space of reduced areadownwardly, means to supply treating gas to the drying chamber by way ofthe distributing space and the louver interspaces, said means comprisingablower, a distributing manifold, and an annular inlet from the manifoldto the distributing space, a cover separating the drying chamber fromthe manifold, means to introduce the material to be treated in finelydivided condition into the drying chamber axially thereof and in thesame general direction as the incoming treating gas, and means toseparate the treating gas and dried material upon its exit from thedrying chamber.

5. Evaporating apparatus comprising a drying chamber of generallycylindrical shape having walls provided with louver openings thereintolongitudinally spaced apart and extending spirally substantiallyparallel to each other, an outer enclosing wall spaced from the saidchamber to provide an annular gas distributing space, means to supplytreating gas to the drying chamber by way of the distributing space,said means comprising a blower, a distributing manifold, and an annularinlet from the manifold to the distributing space with directing vanesadjustably disposed in the annular inlet, a cover separating the dryingchamber from the manifold but providing for the introductiontherethrough of small quantities of gas, means to condition the gasbefore its entry into the manifold as to temperature, pressure, andquantity, means to introduce the material to be treated in finelydivided condition into the drying chamber axially or the cover, and

means to separate the treating gas and dried ma t-erial upon its exitfrom the drying chamber.

6. Evaporating apparatus comprising a drying chamber of generallycylindrical shape having walls provided with openings longitudinallyspaced apart. an outer enclosing wall spaced from the chamber to providean annular gas distributing space, means to supply treating gas to thedistributing space in a downward direc tion, means to impart to the gasin the distributing space prior to its entry into the drying chamber aspiral directional flow, said means comprising a series of directingvanes adjustable to varying angles and disposed at the entrance to thedistributing space.

7. Evaporating apparatus comprising a drying chamber having wallsprovided with openings thereto longitudinally spaced and extendingsubstantially parallel to each other, an outer enclosing wall spacedfrom the said chamber more widely above than below to provide an annulardownwardly extending gas distributing space of gradually reduced area,means to supply treating gas downwardly to said distributing space,means to direct and control the flow of the gas within said distributingspace and drying chamber, the openings connecting the outer distributingspace with the inner treating chamber arranged to direct the treatinggas downwardly along the inside of the chamber walls, and means tointroduce the material to be treated in finely divided condition axiallyof the drying chamber.

8. Evaporating apparatus comprising a drying chamber having wallsprovided with openings thereto longitudinally spaced and extendingsubsupply treating gas to said distributing space at the portion ofgreater capacity, adjustable means to control the direction of flowwithin said distributing space, and means to introduce the material tobe treated in finely divided condition axially of the drying chamber.

9. Evaporating apparatus comprising a. drying chamber of generallycylindrical shape having angles and disposed at the entrance to thedistributing space.

10. Evaporating apparatus comprising ,a drying chamber having wallsprovidedwith openings thereto longitudinally spaced and extendingsubstantially parallel to each other, an outer enclosing wall spacedfrom the said chamber more widely adjacent its inlet to provide anannular gas distributing space of gradually reduced area, means tosupply treating gas to the greater area of said distributing space,means to direct and control the flow of the gas within said distributingspace and drying chamber, the openings connecting the outer distributingspace with the inner treating chamber arranged to direct the treatinggas along the inside of the chamber walls, and means to introduce thematerial to be treated in finely divided condition axially of the dryingchamber.

KRIS'I'IAN SCHULTZ.

